Dental intra-oral x-ray images are taken by using x-ray examination devices which typically include, on the one hand, a multi-jointed arm construction and a radiation source arranged in connection with it and, on the other hand, an image-data receiving means, such as a film or an electric imaging sensor, to be positioned within the patient's mouth in a desired orientation. Typically, to a cover of the x-ray source is attached or arranged attachable an elongated collimator structure to limit an x-ray beam to the image-data receiving means and thus minimise the radiation dose received by the patient. The imaging process includes placing the x-ray device in the proximity of the object area to be imaged and aiming the x-ray beam such that it will meet the sensor in a correct orientation and at a desired angle. Typically, the beam is positioned perpendicularly with respect to the image-data receiver arranged inside the patient's mouth.
One typical intra-oral x-ray device according to prior art is described in patent specification Fl 119008. The device includes, as shown in attached FIGS. 1-4, a control panel 2, a jointed 8, 9 arm construction 3 consisting of several arm parts 5, 6, 7 and an x-ray source 4. The centre axes of the arm parts define a plane where the arm parts 5, 6 can be turned with respect to virtual joint axes defined by the jointings 8, 9. The x-ray source 4 is connected substantially to an end of the furthest arm part 5 by a structure 10 and 11, which enables turning the x-ray source with respect to both a vertical and a horizontal axis. The control panel 2 is attached to a horizontal arm 7 supporting the outermost arm parts 5, 6 of the arm construction.
Patent specification US2007/0237291 describes an arrangement in which an arm construction supporting a radiation source is arranged into connection with a dental care apparatus.
Generally speaking, the arms of intra-oral x-ray devices have been implemented to enable adjusting location of the x-ray source at least in height dimension, i.e. arms structures which enable moving the x-ray source only on one horizontal plane do not in practise fall within interest of skilled men of this field—also due to a skilled man presuming that applying such solutions to enable supporting a fairly heavy radiation source which is to be placed at the end of the arms structure would be likely to turn out to be problematic, when regarding arms structures turning on a horizontal plane there has been no need to take into consideration any counterbalancing needs corresponding those caused by gravity.
Typically, an electricity and signal cabling related to the use of the radiation source has been arranged to pass through the arm construction of the intra-oral x-ray device. Furthermore, the arm construction must be balanced in one way or the other, in order to be able to move the arms more lightly and, additionally, in order the radiation source staying at a desired position also otherwise than by holding it. This typically means arranging springs within the arms. The arm parts are typically hollow pieces manufactured of rigid material. Pulling the cables though such arms when assembling the arm construction is awkward, as is setting the springs within such elongated hollow structures. In many arrangements, the arm construction has not been covered at the point of the jointing, whereby the cables left unprotected are prone to damages and otherwise to wear within this area, due to forces which are applied to them when turning the arm construction into different positions.